PASTIS: Bayesian extrasolar planet validation. I. General framework, models, and performance

By R. D'iaz, J. Almenara, A. Santerne, C. Moutou, A. Lethuillier, Magali Deleuil 1. Aix Marseille Universit'e, Cnrs, Lam, France., 2. O. A. D. L. D. Geneve and 1 more. 2014

124 citations recorded by the source corpus.

A large fraction of the smallest transiting planet candidates discovered by the Kepler and CoRoT space missions cannot be confirmed by a dynamical measurement of the mass using currently available observing facilities. To establish their planetary nature, the concept of planet validation has been advanced. This technique compares the probability of the planetary hypothesis against that of all reasonably conceivable alternative false positive (FP) hypotheses. The candidate is considered as validated if the posterior probability of the planetary hypothesis is sufficiently larger than the sum of the probabilities of all FP scenarios. In this paper, we present pastis, the Planet Analysis and Small Transit Investigation Software, a tool designed to perform a rigorous model comparison of the hypotheses involved in the problem of planet validation, and to fully exploit the information available in the candidate light curves. pastis self-consistently models the transit light curves and follow-up observations. Its object-oriented structure offers a large flexibility for defining the scenarios to be compared. The performance is explored using artificial transit light curves of planets and FPs with a realistic error distribution obtained from a Kepler light curve. We find that data support the correct hypothesis strongly only when the signal is high enough (transit signal-to-noise ratio above 50 for the planet case) and remain inconclusive otherwise. PLAnetary Transits and Oscillations of stars (PLATO) shall provide transits with high enough signal-to-noise ratio, but to establish the true nature of the vast majority of Kepler and CoRoT transit candidates additional data or strong reliance on hypotheses priors is needed.

Subfields: Astronomy and Astrophysics, Instrumentation

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In Astronomy and Astrophysics

1. Timothy Morton
2. J. Johnson
3. D. Charbonneau
4. A. Mann
5. Daniel Foreman-Mackey
6. David W. Hogg
7. D. Latham
8. Jon Fortney

In Instrumentation

1. Timothy Morton
2. J. Johnson
3. Daniel Foreman-Mackey
4. A. Mann
5. David W. Hogg
6. B. Bowler
7. D. Latham
8. B. Montet

Citations in the corpus

• STELLAR AND PLANETARY PROPERTIES OF K2 CAMPAIGN 1 CANDIDATES AND VALIDATION OF 17 PLANETS, INCLUDING A PLANET RECEIVING EARTH-LIKE INSOLATION (2015, methodology): “Similar in spirit to other published methods of probabilistic validation, such as BLENDER (Torres et al. 2011) and PASTIS (Díaz et al. 2014), it has the advantage of being computationally less demanding and fully automated, and thus easily applied in batch to a large number of candidates.”
• One of the closest exoplanet pairs to the 3:2 mean motion resonance: K2-19b and c (2015, methodology): “To estimate the posterior probability that the K2-19 data are produced by one of the aforementioned scenarios, we used the PASTIS software (Díaz et al. 2014; Santerne et al. 2015) to model the K2 photometric measurements6.”
• SOPHIE velocimetry of Kepler transit candidates XVII. The physical properties of giant exoplanets within 400 days of period (2015, methodology): “For that, we analysed the data with the MCMC algorithm of the PASTIS software (Díaz et al. 2014a).”